How to determine failure on Mohrs Circle

[EzaMoo]

I have already drawn the circle and am happy and confident with it, but the question asks me to determine if failure has occurred and I am unsure of how to tell, I guess I don't know how to read the circle and interpret what it means.

Can anyone describe to me how you tell if failure has occurred on a mohrs circle.

 

[nvn]

EzaMoo: I assume this is ductile material. You could obtain the maximum and minimum principal stress from your Mohr circle. Then compute von Mises stress, sigma_vm, using sigma1 and sigma3. Then compute the stress level w.r.t. yielding, Ry = FSy*sigma_vm/Sty, where FSy = yield factor of safety, and Sty = material tensile yield strength. If Ry ≤ 100 %, the analysis indicates the component is adequate. If Ry > 100 %, the analysis indicates failure.

For design, FSy > 1.0. For failure analysis only, not design, FSy = 1.0.

Keep in mind, the above failure theory (von Mises theory) applies only[/color] to isotropic, ductile materials, such as isotropic, ductile metals. Other material types require different failure theories. You must use a failure theory applicable to your material type.